[Smarty variables] Fix contribution tab to work with escape by default

[eileenmcnaughton]

Overview

This removes some isset that affect contact contribution tab if escape on output is enabled.

Before

Fatal on contribution (if they have contributions) with modifiers enabled by default

After

loads

Technical Details

This might regress some smarty e-notices. I think if tests pass that is OK at this stage
as we never eliminted them & getting to security enablable seems like a higher priority

Comments

[civibot]

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[eileenmcnaughton]

unrelated fail (date specific - failing elsewhere)